LÖVE

Code: Select all

EnemyFormation = Class{}

function EnemyFormation:init()
  self.x = 10
  self.y = 10
  self.rows = 4
  self.cols = 8
  self.xMin = 0
  self.xMax = self.cols * 40 - 20
  self.yMin = 0
  self.yMax = self.rows * 30 - 10
  self.dx = 30
  self.spacing = 2
  self.enemy = self:generateEnemyFormation(self.cols, self.rows, self.spacing)
  self.timer = 0
  self.stepTime = 1
  self.accelerator = 0.9
  self.xStep = (VIRTUAL_WIDTH - (ENEMY_WIDTH * (self.spacing * (self.cols - 1) + 1))) / 20
  self.yStep = 10
  self.edgeFlag = false
  self.stepFlag = true
  self.width = self.cols * 40 - 20
  self.enemyLasers = {}
end

function EnemyFormation:update(dt)
  self.timer = self.timer + dt

  self.xMin = self:xMinCheck()
  self.xMax = self:xMaxCheck()

  -- Simple timer to "step" the enemyFormation across screen and toggle edgeFlag
  if self.timer > self.stepTime then
    if not self.edgeFlag then
      self.x = self.x + self.xStep
    elseif self.edgeFlag then
      self.y = self.y + self.yStep
      self.stepTime = self.stepTime * self.accelerator
      self.edgeFlag = false
    end

    self:fireEnemyLaser()
    self.timer = 0
    self.stepFlag = not self.stepFlag
  end

  for key, laser in pairs(self.enemyLasers) do
    laser:update(dt)
  end
  
  -- Track position of bounding box to move Enemy instances as a group vs. individually
  if self.x + self.xMax >= VIRTUAL_WIDTH then
    self.edgeFlag = true
    self.xStep = -self.xStep
    self.x = VIRTUAL_WIDTH - self.xMax - 1
  elseif self.x + self.xMin < 0 then
    self.edgeFlag = true
    self.xStep = -self.xStep
    self.x = 1 - self.xMin
  end
end

-- Pass x, y coordinates of the enemyFormation box for Enemy instances to use as a reference point.
function EnemyFormation:render()
  for key, enemy in ipairs(self.enemy) do
    if enemy.isActive then
      enemy:render(self.x, self.y, self.stepFlag)
    end
  end

  for key, laser in pairs(self.enemyLasers) do
    if laser.y > VIRTUAL_HEIGHT then
      table.remove(self.enemyLasers, key)
    end
    laser:render()
  end
end

-- Function to generate all enemy instances within the formation
function EnemyFormation:generateEnemyFormation()
  local enemies = {}
  for row=1, self.rows do
    for col=1, self.cols do
      table.insert(enemies, Enemy(12, 12, row, col, self.spacing))
    end
  end
  return enemies
end

-- Function to determine the leftmost x position of enemy formation
function EnemyFormation:xMinCheck()
  for col=1, self.cols do
    for row=1, self.rows do
      if self.enemy[(col - 1) + (row - 1) * self.cols + 1].isActive then
        return ((col - 1) * 40)
      end
    end
  end
end

-- Function to determine the rightmost x position of enemy formation
function EnemyFormation:xMaxCheck()
  for col=self.cols, 1, -1 do
    for row=self.rows, 1, -1 do
      if self.enemy[(col - 1) + (row - 1) * self.cols + 1].isActive then
        return (col * 40) - 20
      end
    end
  end
end

function EnemyFormation:fireEnemyLaser()
  local shooter = self:selectShooter()
  local laser = Laser(shooter.xOffset + shooter.width * 0.5 + self.x, shooter.yOffset + shooter.height + self.y, 1)
  laser.isVisible = true
  table.insert(self.enemyLasers, laser)
end

function EnemyFormation:selectShooter()
  while true do
    local col = math.random(self.cols)
    for row = self.rows, 1, -1 do
      if self.enemy[(row-1) * self.cols + col].isActive then
        return self.enemy[(row-1) * self.cols + col]
      end
    end
  end
end

Code: Select all

Enemy = Class{}

function Enemy:init(width, height, row, col, spacing)
  self.xOffset = (col - 1) * ENEMY_WIDTH * spacing
  self.yOffset = (row - 1) * ENEMY_HEIGHT * spacing
  self.width = width
  self.height = height
  self.isActive = true
  self.isShooter = false
end

function Enemy:render(formationX, formationY, stepFlag)
  if stepFlag then
    love.graphics.setColor( gColorPalette['yellow'], 1)
  else
    love.graphics.setColor( gColorPalette['lgreen'], 1)
  end
  love.graphics.rectangle("fill", formationX + self.xOffset, formationY + self.yOffset, self.width, self.height)
end

Code: Select all

Shelter = Class{}

function Shelter:init()
  self.width = 35
  self.height = 15
  self.x = VIRTUAL_WIDTH / 5
  self.y = VIRTUAL_HEIGHT - 50
  self.shelters = {{x=self.x - self.width / 2, y=self.y},
                   {x=self.x * 2 - self.width / 2, y=self.y},
                   {x=self.x * 3 - self.width / 2, y=self.y},
                   {x=self.x * 4 - self.width / 2, y=self.y}}
end

function Shelter:render()
  love.graphics.setColor(gColorPalette['white'], 1)
  for key, shelter in ipairs(self.shelters) do
    love.graphics.rectangle("fill", shelter.x, shelter.y, self.width, self.height)
  end
end

Code: Select all

function PlayState:enter(params)
	self.shelters = {}

	for i = 1, 4 do -- 4 here can be a variable!
		local shelter = Shelter()
		shelter.x     = something
		shelter.y     = something
		table.insert(self.shelters, shelter)
	end
end